all mcdonald's. ♪ ba da ba ba ba somewhere in america... the slightest breeze harbors immense power. the tallest buildings leave the lightest footprints. a fifty-ton train makes barely a mark on the environment. and a country facing climate change finds climate solutions. somewhere in america, we've already answered some of the nation's toughest questions. and the over sixty thousand people of siemens are ready to do it again. siemens. answers. >>> we are back with a look at the top of the charts this morning -- >>> the earth day festival on the mall is this sunday. and the earth day report, there's a war going on in the potomac river basin. it to to stop invaders that spread to the ecosystem and cost $120 billion every year. >> when you go over the potomac river at chain bridge or the american legion bridge you are looking down at some of the rarest habitats on earth. some of those plant communities are found nowhere else but the potomac gorge. >> reporter: but this precious ecosystem is under attack from foreign invaders. >> it out compet